This invention relates generally to electrical connectors, and more particularly, to a connector having electrostatic discharge (ESD) protection.
Some electrical connectors have a mating end wherein conductive terminals are exposed for engagement with the terminals of a mating connector. This is common in a right angled connector used for interconnecting circuit boards such as a back plane and a daughter board. The back plane typically has a connector, commonly referred to as a header, that mates with a daughter board connector, commonly referred to as a receptacle. Portions of the terminals in the receptacle are often exposed for engagement with the terminals of the header connector.
When mating the connectors, opposite charges at the connector interface may result in an electrostatic discharge between the two connectors. In fact, electrostatic discharges can be generated simply by a person approaching or touching the connector interface or touching the terminal contacts. Generally, very little current is associated with an electrostatic discharge; however, the voltage can be high enough to damage or destroy certain types of electrical devices such as semiconductor devices. Consequently, when the connector contacts or terminals are electrically associated with such devices on a circuit board, the electrostatic discharge may damage or destroy the electrical devices on the circuit board.
In order to alleviate the electrostatic discharge problem, some electrical connectors include features to provide ESD protection. In at least some connectors, ESD protection is provided with a shield in the form of a plate, bar, or the like located proximate the connector interface and connected to ground on or proximate the connector. However, the provision of such ESD shields add to the cost of the connector. Provision must be made in the connector housing for mounting the ESD shield and an ESD pathway must be provided to ground the shield. These structures also add to the cost and complexity of the connector.
In at least some right angled receptacle connectors, the receptacle includes a plurality of wafers, each of which includes signal carrying traces and ground traces along with signal and ground contact pads. Often, the contact pads and traces are confined to a front surface and a large ground plane is disposed on the rear surface for shielding purposes. Typically, the ground plane covers a substantial portion of the rear surface of the wafer; however, for signal integrity reasons, the ground plane does not generally extend to an area behind the contact pads. To effectively shield the connector, each of the wafers needs to be shielded from ESD.
A need remains for a connector that provides ESD shielding in a cost effective manner and without adding to the size or complexity of the connector.